Cut-off-valve gear



(No Model.)

A. L. HARRISON. GUT-OFF VALVE GEAR.

Patented Apr.12s, 1889.

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UNTTED STATES PATENT "ANDREXV L. HARRISON, OF WILMINGTON, NORTHCAROLINA.

CUT-OFlF-VALVE G EAR.

SPECIFICATION forming part of Letters Patent No. 401,831, dated April23,1889.

Application filed May 17, 1888.

To all whom it may concern:

Beit known that I, ANDREW LANGDON HAR- RISON, of lVilmington, in thecounty of lflanover and State of North Carolina, have invented a new andImproved Out-Off-Valve Gear for Engines, of which the following is afull, clear, and exact description.

My invention relates to a cut-off specially adapted for marine engines,and has for its objects to provide a variable cut-off which will worksteam expansively at all points from the dead-center to the full stroke,and wherein the speed of the engine may be reduced at will withoutclosing the throttle, and also to provide an improvement upon what isknown as the Stevens cut-off.

The invention consists in the construction and combination of theseveral parts, as will be hereinafter fully set forth, and pointed outin the claims.

Reference is to be had to the accompanying drawings, forming a part ofthis speoification, in which similar figures of reference indicatecorresponding parts in all the views.

Figure 1 is a front elevation of a rock-shaft, partly in section, withmy improvement applied. Fig. 2 is an end view of the same, and Fig. 3 isa partial plan view.

In carrying out the invention the rook-shaft 10 is journaled in theusual manner and provided with fingers 11 near one end and adownwardly-extending arm, 12, at the opposite end. A second arm, 13,provided with a horizontal projection, 14, at the upper end, is attachedto the rock-shaft and extends downward parallel with the aforesaid arm12, the outer arm, 13, being connect-ed with the rock shaft, preferably,through themedium of bolts 15, passing through the outer arm into theend of said rock-shaft, as best illustrated in Figs. 1 and 2.

By reason of the projection 14 a space is made to intervene thecontiguous faces of the arms 12 and 13, and the said arms, near theirlower ends, are provided with aligning and straight rectangularlongitudinal slots 16 and a vertical longitudinal bore, 17, which boreextends from the upper end of the arm 13,1ikewise the upper end of therock-shaft, down through the lower ends of the said arms, as bestillustrated in Fig. 1.

An eccentric -pin, 18, is projected trans= Serial No. 274,188. (Nomodel.)

versely through the said slots 16, one end of which pin is threaded andextends beyond the inner arm, the opposite end being provided with asuitable cap or washer, 19. That portion of the pin 18 which is adaptedto slide in the slots 16 is made rectangular and provided with avertical aperture, 20, aligning the bore 17 of the respective arms.

Beneath the rectangular portion of the eccentric-pin nuts 21 are held toslide in the slots 16, the said nuts being adapted for the reception ofa vertical rod, 22, threaded at its lower extremity, which rods areprovided at their upper ends with a pinion, 23, and ext-end downwardthrough the bore 17, the aperture 20 of the eccentricpin, and also outthrough the lower ends of the arms, at which point they are providedwith a suitable lock-nut, 24.

A vertical rod, 25, is held to turn in an aperture produced in the armprojection or extension 14, the upper end of the said rod being providedwith a hand-wheel, 26, and a gear, 27, below said hand-wheel, adapted tomesh with the respective pinions 23. The eccentric rod or hook, which isnot shown, is attached to the eccentric-pin in the usual manner.

A washer, 28, is passed over the extended curved end of theeccentric-pin 18 to a bearing against the inner face of the arm 12, andthe said washer is held in position by a nut, 29. lVhen the nut has beenscrewed up to proper position, the apertured end of a wrenchbar, 30,ispassed over said nut and detachably secured thereon through the mediumof a set screw or other approved or equivalent device. Thus,inoperation, while the rock-shaft is yet in motion, by manipulating thehand-wheel 26 the eccentric-pin may be raised or lowered, as desired,and clamped in position by means of the wrench-bar 30.

It will thus be observed that I provide a mechanical device adapted forattachment to the end of the rock-shaft, whereby the adj ust-. ing ofthe lead of the steam-valves and taking off the lead and putting it onmay be accomplished at will with the engine in motion, the said enginenot having to be stopped. to roll the eccentric on the main shaft tosecure this result, as is at present the case. As the slots in the armsare not cut on a radius from the center of the main shaft, when the pinis moved up or down in them the lead of the valves is changed, also thelift or throw of the valves. Consequently the steam is enabled to becutoff shorter or longer to change the speed of the engine slow or fast,as desired, leaving the throttle-valve wide open at all times, and atthe same time permitting the steam to be worked expansively at alltimes.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

1. The combination, with the rock-shaft of an engine, of parallel spacedarms secured to one end of said rock-sh aft, provided with aligning andstraight rectangular slots near their lower ends, an eccentric-pinsliding in said slots, a nut also sliding in the slots below the saidpin, rods projected downward through the arms and the pins and engagingthe nuts, and a means, substantially as shown and described, formanipulating said rods, whereby provision is made for changing the leadof the valves, and also the lift or throw of the said valves, as setforth.

2. The combination, with the rock-shaft of an engine and spaced armssecured at one end, provided with an aligning rectangular slot and avertical bore extending longitudinally from end to end, of aneccentric-pin sliding in said slots, a nut also sliding in the slotsbelow the pin,rods threaded at their lower ends and projected throughthe bore of the arms and engaging said nuts, pinions attached to theupper end of said rods, and a hand-wheel journaled in the rock-shaftabove the pinion and provided with a gear-wheel meshing with the same,as and for the purpose specified.

3. The combination, with the rock-shaft of an engine and spaced armssecured at one end, provided with an aligning rectangular slot and avertical bore extending longitudinally from end to end, of aneccentric-pin sliding in said slots, anut also sliding in the slotsbelow the pin,rods threaded at their lower ends and projected throughthe bore of the arms and engaging said nuts, pinions attached to theupper end of said rods, a hand-wheel j ournaled in the rock-shaft abovethe pinions and provided with a gear-wheel meshing with said pinions,and means, substantially as described, for locking the eccentric-pin ina fixed position, as and for the purpose specified.

ANDREW L. HARRISON. Witnesses:

J osH. G. WRIGHT, S. J. BRYAN.

